Abstract: Objective To study the changes of peripheral blood cells of irradiated Beagle dogs, in order to set up low dose radiation-injured dog model for evaluating new drug. Methods Twenty-four male Beagle dogs were divided into five groups, 1.1 Gy irradiated was the control group, and the rest four groups dog were shielding irradiated using lead plate, which invovled in 0.3 Gy continuous five days, 0.6 Gy continuous three or five days, and 1.0 Gy. Blood samples were collected and the numbers of peripheral blood cells were counted using a microcell counter. Clinical index such as body temperature, body weight, and clinical symptoms were observed. Results The survival rate was 33% in group of 0.6 Gy irradiation for continuous five days, and the rest dogs from other groups were all survived. The number of white blood cells and platelets decreased from first to twenty-third day in dogs from group of 0.6 Gy irradiation for continuous three days, and decreased from first to twenty-fifth day in dogs from group of 0.6 Gy irradiation for continuous five days. The number of white blood cells decreased from seventh to twenty-first day in dogs from group of 1.0 Gy irradiation, and platelets decreased from eleventh to seventeenth day. The number of red blood cells decreased from fifth to fiftenth day in dogs from group of 0.6 Gy irradiation for continuous three days and hemoglobins decreased on fifth day. Red blood cells decreased from thirteenth to twenty fifth day in group of 0.6 Gy irradiation for continuous five days and hemoglobins decreased from thirteenth to twenty fifth day. Conclusion Based on survival rate, clinical symptoms and peripheral blood cells, the group of 0.6 Gy irradiation for continuous three days was chosen as low dose radiation-injured dog model to evaluate new drug.

Key words: Low dose radiation, Beagle dog, Radiation, Peripheral blood cells